I bought a new plug to hook up to the boat trailer and when i was hooking it up i noticed on the old one the blue for the brakes was hooked up for back up not on the brakes. So on the new one i hooked it up correctly so the blue is on the electric brake connection. When i picked up the boat from the shop and i got home as soon as i started to back up the brakes locked. I have no idea why so i recconected the blue to the back up and it worked no problem. I'm not sure what is going on. Does anyone have any good tips or ideas on this issue?
With the blue wire connected to it, it is in constant bypass mode since the blue is a constant 12v signal. As said above, it should be connected to the back up lights so it only gets a signal when in reverse.